BACKGROUND: Several studies have demonstrated that Helicobacter pylori (H. pylori) eradication does not affect metabolic control in diabetic patients. The prevalence of H. pylori infection and reinfection rate in adult diabetic patients seems to be higher than in controls. AIM OF OUR STUDY: To evaluate the reinfection rate of H. pylori three years after a standard eradicating treatment and the late effect of eradication upon metabolic control in young diabetic patients. METHODS: We enrolled 75 diabetic patients and 99 controls, from previous our studies in which we had evaluated H. pylori infection. In all subjects we re-evaluated the presence of H. pylori by means of C-13-Urea Breath Test, metabolic control and the prevalence of gastrointestinal symptoms. The effect of age, sex and socio-economic factors on H. pylori reinfection were also evaluated. RESULTS: The prevalence of H. pylori infection was higher in diabetic patients (17/69, 24%) than in dyspeptic controls of similar age, gender and socio-economical status after three years of follow-up. The reinfection rate was higher in diabetic patients than in controls. Multivariate analysis confirmed that age and socio-economical status were independently associated with H. pylori reinfection. CONCLUSIONS: Young patients with diabetes present a higher risk of H. pylori gastric reinfection than controls. In addition, age and mean annual income are associated with reinfection.